1. Technical Field
The present invention relates to a tilting device, and in particular, to a vibration type tilting device in which the mass moment of inertia is decreased for superior vibration performance.
2. Description of the Related Art
An image projection device using digital light processing (DLP), in which the mosaic phenomenon in pixels, a problem in regular liquid crystal display (LCD) imaging devices, is eliminated to improve the ability to reproduce original colors, is used widely in theaters, conference rooms, and projection TV's, etc. The image projection device can be divided into a Front Projection device and a Rear Projection device according to the projection method.
The Front Projection device adopts the method of projecting image signals from the front, and is generally used in theaters, conference rooms, etc. On the other hand, the Rear Projection device adopts the method of projecting image signals from the rear of the screen. The Rear Projection device is commonly used in the form of projection TV's. In particular, Rear Projection devices are used more often than Front Projection devices, because of its ability to display a relatively bright image even in a bright environment.
FIG. 1 is a perspective view illustrating a conventional image projection device, and FIG. 2 is a schematic drawing illustrating the pixel structure shown on a screen by a conventional image projection device.
As shown in FIG. 1, a conventional image projection device comprises a lamp 11, a condenser lens 13 which collimates and irradiates light emitted from the lamp 11, a color wheel 15 which separates the collimated white light into red (R), green (G), and blue (B) colors and illuminates ⅓ for every frame, a collimation lens 17 which irradiates parallel the light emitted from the color wheel 15 for each color, a digital micro-mirror panel 19 (hereafter referred to as “DMD”) which adjusts the reflection angle for each pixel of the light collimated from the collimation lens 97 for each color to form a picture, and a projection lens 21 which projects the light from the DMD to a large display of a screen S.
On the DMD 19 are formed numerous micro-mirrors (not shown), which are minute in size and are associated with a pixel structure on a silicon wafer, and these micro-mirrors convert the path of the incident light on/off by individually undergoing a highly rapid tilting motion according to the digital information provided to the DMD 19 by a controller. The pixels controlled individually by the DMD 19 are magnified through a projection lens 21 so that a large display picture is formed on the screen S.
As described above, since conventional image projection devices form a large display simply through the magnified projection of the small original picture, there is the problem that the picture quality is degraded due to the grid pattern formed between each pixel P, as seen in FIG. 2. Also, there is a problem in that when the picture moves rapidly or where the line of sight of the viewer moves rapidly, the picture is formed on the screen with rainbow colors showing where the contrast ratio is great, for example where there are black stripes on a white background, or with the grid pattern between each pixel notably significant.